Conventionally, as the commonest imaging method for X-ray imaging, the film/screen method has been used. In this method, imaging is performed by using a combination of a light-sensitive film and a phosphor having sensitivity to X-rays. Phosphors made of a rare-earth material that emits light upon being irradiated with X-rays are held in tight contact with the two surfaces of a light-sensitive film. X-rays transmitted through an object to be imaged are converted into visible light by the phosphors, and the light is captured by the light-sensitive film. The latent image formed on the light-sensitive film is developed by a chemical treatment, thereby visualizing the image.
As the second imaging method, a method called the computed radiography (CR) method has also been put into practice. In this method, a radiation transmission image is temporarily stored as a latent image in a phosphor, and the latent image is read out afterward by irradiating the phosphor with exciting light. When, for example, a certain type of phosphor is irradiated with radiations such as X-rays, αrays, βrays, γrays, electron rays, or ultraviolet rays, part of the energy of the radiations is stored in the phosphor. It is also known that when this phosphor is irradiated with exciting light such as visible light, the phosphor exhibits photostimulated luminescence in accordance with the stored energy.
A phosphor exhibiting such a property is called a storage phosphor or photostimulated phosphor. Radiation image information recording/playback systems have been proposed in, for example, Japanese Patent Laid-Open Nos. 55-12429 and 56-11395. In such a system, by using this storage phosphor, radiation image information of an object such as a human body is temporarily stored in a storage phosphor sheet. Thereafter, this storage phosphor sheet is scanned with exciting light such as laser light to produce photostimulated luminescence light. By photoelectrically reading the obtained photostimulated luminescence light, an image signal is acquired. On the basis of this image signal, a radiographic image of the object is output as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT.
With the recent advances in semiconductor process techniques, an apparatus for taking an X-ray image by using a semiconductor sensor in the same manner has been developed as the third imaging method. A system of this type is advantageous over a conventional radiographic system in that it can record images in a very wide radiation exposure range. More specifically, X-rays in a wide dynamic range are read by a photoelectric conversion means to be converted into an electrical signal. By using this electrical signal, a radiographic image is output as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT. This makes it possible to obtain a radiographic image that is robust against variations in the amount of exposure to radiation.
FIG. 6 is a schematic view of a radiation imaging system using the above semiconductor sensor. An X-ray imaging apparatus 1 incorporates an X-ray detection sensor 2 having a detection surface constituted by a plurality of two-dimensionally photoelectric conversion elements. An object to be imaged is irradiated with the X-rays emitted from an X-ray generating unit 3 of the X-ray imaging apparatus 1. The X-rays transmitted through the object S are detected by the X-ray detection sensor 2. The image signal output from the X-ray detection sensor 2 is subjected to digital image processing in an image processing unit 4. The resultant data is then displayed as an X-ray image of the object S on a monitor 5.
With recent improvements in information networks in hospitals, information systems called a hospital information system (HIS), a radiology information system (RIS), a picture archiving and communication system (PACS), and the like have been developed as systems which handle information on networks. These systems are closely related to the operation of X-ray imaging apparatuses.
The hospital information system handles overall in-hospital management information such as patient information (e.g., patient IDs, patient names, sexes, and dates of birth) and accounting information. The radiology information system manages information concerning imaging operation, e.g., receiving an imaging request from a diagnosis/treatment department and outputting an imaging request to the radiology department upon clarifying a specific patient, specific region, and specific imaging equipment to be used for imaging operation. The picture archiving and communication system performs archiving management of image data, e.g., archiving sensed image data and retrieving and distributing images upon reception of visual check requests for past images.
X-ray imaging apparatuses in a hospital include a stationary apparatus that is fixed in an imaging room and a mobile apparatus which can move in the hospital. The mobile apparatus can be carried to a patient's room, operating room, intensive care unit, accident ward, or the like to perform X-ray imaging for a patient who cannot come to the imaging room. Obviously, the stationary X-ray imaging apparatus is connected online to each information system in the hospital. However, the mobile X-ray imaging apparatus is not connected to any information system in the hospital.
FIG. 7 shows the schematic arrangement of a conventional information system in a hospital.
An information system 11 is connected to a radiology information system 12 and exchanges information concerning patient information, imaging, and the like. Upon reception of an X-ray imaging request, the radiology information system 12 generates X-ray imaging request documents with necessary information being completed, and outputs them, as documents 16. In a large-scale hospital, a plurality of mobile X-ray imaging apparatuses 13, 14, and 15 are prepared in each diagnosis/treatment department or ward, and a plurality of X-ray imaging technicians simultaneously perform imaging.
In order to make the mobile X-ray imaging apparatuses 13, 14, and 15 respectively perform requested X-ray imaging operations, an operator who determines tasks sorts the documents 16 (to documents 17, 18, and 19) according to the X-ray imaging. apparatuses to be used, and assigns the respective mobile X-ray imaging apparatuses to the X-ray imaging technicians in charge. Upon reception of the request, each X-ray imaging technician moves together with a mobile X-ray imaging apparatus in a corresponding shared range to perform imaging. After the imaging, the technician inputs the imaging result to the radiology information system 12 through a request document.
Upon reception of requests, each X-ray imaging technician rearranges first the distributed request documents in imaging order. In this case, the imaging technician rearranges the request documents based on the patients' room numbers written on the documents in consideration of the arrangement of the rooms and the most efficient imaging route. Each imaging technician then moves together with a mobile X-ray imaging apparatus in a corresponding shared range and performs imaging in accordance with the order.
The imaging apparatus designed to acquire external information concerning imaging operation through a portable storage medium or communication means is known in Japanese Patent Laid-Open No. 2002-125960, which is a portable imaging apparatus designed to acquire sensed images by using an imaging means including photoelectric conversion elements.
As described above, conventional mobile X-ray imaging apparatuses are not connected to the network in a hospital. According to the film/screen method, since no image is digitalized, both the stationary and mobile X-ray imaging apparatuses are not generally connected to the network in a hospital. In the computed radiography method, a reading device for photostimulated phosphors is of a stationary type and is generally connected to the network in a hospital.
In using a mobile X-ray imaging apparatus, photostimulated phosphors are stored in cases called cassettes one by one and carried to be used for imaging as in the case of ordinary films, and each cassette having undergone imaging operation is carried to a reading device to be read. The mobile X-ray imaging apparatus is not therefore connected to the network in a hospital.
With a recent improvement in the performance of mobile X-ray imaging apparatuses and for the purpose of reducing the burdens on patients to be imaged, an increasing number of imaging operations are performed by using mobile X-ray imaging apparatuses. The conventional operation based on documents has posed problems in terms of poor input/output efficiency and poor reliability related to errors in writing, posting errors, and the like. In addition, since each technician determined an imaging order, he/she did not always follow the most efficient, shortest route, resulting in poor imaging efficiency.
In the third method, when an X-ray detection sensor is to be used, a stationary X-ray imaging apparatus is generally connected to the network in a hospital. When an X-ray detection sensor is to be used for a mobile X-ray imaging apparatus, since a control device and image storage device for the X-ray detection sensor are incorporated in the mobile X-ray imaging apparatus, the operation efficiency becomes very poor unless the apparatus has some means for connecting to the network in the hospital.
For example, at times it becomes necessary to manually input patient information or temporarily store image information in a portable medium and send the information to an information system through the medium. The operation time may undesirably become long or a data entry error may occur. In addition, since there has been no system for determining an imaging order, the imaging efficiency has been poor. According to the mobile (portable) imaging apparatus disclosed in Japanese Patent Laid-Open No. 2002-125960 described above, there is no need to manually input patient information, and imaging information can be efficiently acquired. If, however, operation and the like using a plurality of mobile imaging apparatuses are assumed, it is necessary to select imaging information for each mobile imaging apparatus in externally acquiring imaging information.